Talk:Metastability
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[edit] Metastability vs hysteresis
I think that the article would gain from distinguishing between the words metastable equilibrium and hysteresis. A system at metastable equilibrium is well described by Statistical mechanics and the fluctuations obey the fluctuation dissipation theorem. On the other hand hysteresis refers to the fact that most physical systems do not reach equilibrium instantaneously.
EDIT: Perhaps it is better to write it the following way:
A metastable system can equilibrium system for all purposes. As an example the state of a metastable system is fully described by the value of temperature and pressure.
[edit] Explaining metastability
When I have to explain metastability, I always use the example of atomic nuclei. Iron is the only stable atomic nucleus. The rest of the atomic nuclei are only metastable. Nevertheless we can use statistical mechanics to describe chemical systems. The key feature here is separation of time scales. The timescale for atomic processes is much longer than the time scale of chemical reactions.
Actually chemical substances are another example of metastability. In quantum chemistry they have several methods for calculating the speed of a chemical reaction. All these methods rely on a crucial assumption that the vibration of the molecule is well described by a thermal equilibrium distribution. In other words they rely on an assumption of metastability. Once again the key assumption is separating time scales. The time needed to attain vibrational equilibrium is shorter than the inverse reaction rate.
[edit] Created two subarticles
I created two subarticles in order to be able to distinguish and specialize them.--Carl Hewitt 04:43, 21 July 2005 (UTC)
